查看当前日志模式与数据库信息：
SELECT log_mode FROM v$database;
SELECT dbid, name, created, log_mode FROM v$database;
切换归档模式（需停机到 mount 再打开）：
shutdown immediate;
startup mount;
ALTER DATABASE ARCHIVELOG;
ALTER DATABASE OPEN;
归档相关查询与维护：
SELECT recid, stamp, thread#, sequence#, name FROM v$archived_log;
SELECT dest_name, status, destination FROM v$archive_dest;
ALTER SYSTEM ARCHIVE LOG ALL;
重做日志组与成员管理：
SELECT * FROM v$log;
SELECT * FROM v$logfile;
ALTER DATABASE ADD LOGFILE GROUP 4 (‘/u02/oradata/redo04a.log’,‘/u03/oradata/redo04b.log’) SIZE 100M;
ALTER DATABASE DROP LOGFILE GROUP 4;
ALTER DATABASE ADD LOGFILE MEMBER ‘/u02/oradata/redo01b.log’ TO GROUP 1;
ALTER DATABASE DROP LOGFILE MEMBER ‘/u02/oradata/redo01b.log’;
强制日志切换与检查点：
ALTER SYSTEM SWITCH LOGFILE;
ALTER SYSTEM CHECKPOINT;
归档目的地空间与清理（RMAN）：
SELECT space_limit/1024/1024/1024 AS quota_g, space_used/1024/1024 AS used_m,
space_used/space_limit*100 AS used_pct, number_of_files
FROM v$recovery_file_dest;
ALTER SYSTEM SET DB_RECOVERY_FILE_DEST_SIZE=40G;
RMAN> LIST ARCHIVELOG ALL;
RMAN> DELETE ARCHIVELOG UNTIL TIME ‘SYSDATE-1’;
RMAN> CROSSCHECK ARCHIVELOG ALL;
RMAN> DELETE EXPIRED ARCHIVELOG ALL;
以上 SQL 覆盖归档模式切换、日志组维护、空间监控与归档日志生命周期管理。